Running Rich

[xboxrox]

Installed new spark plugs today; check out the old ones with 2,000 miles wear:

Running Rich..!

The blackest plug had a broken plug wire...

What can cause 11 mpg..?

George

[geezer101]

Maybe the EGR valve is clogged up. This will affect your MPG and make it run crappy. Got a feeling there's more to it though. What is your ignition coil like? They normally work OK for 10 to 15 years max, then start breaking down pretty badly. Does your truck have an O2 sensor in the exhaust system (part of the electronic carb management junk)? Could be toast - that will definitely affect your engine performance. Is the auto choke on the carb still working? Another culprit of wrecking MPG and engine performance.

[Giovanni89]

Do you have the stock carb or a weber conversion? I don't really know anything about the mikuni, but in general, a torn power valve diaphragm, or stuck power valve will cause any carb to dump fuel down the barrel. In my experience the diaphragms fail suddenly.
As usual, Geezer is on point with all of his suggestions

[xboxrox]

STOCK TRUCK w/ Mikuni carburetor

Thanks gents; I will do my best (over time) to address the things to check in your replies ~ for sure..! Gas is too expensive..!

Original Japanese ignition coil was replaced two weeks ago with a Borg Warner Made in China coil...

One other item I just noticed (see my photos) the vacuum hose routing label/sticker on the hood shows the distributor vacuum advance line going somewhere (???) that is different than what I connected, yikes..! That label is hard to read... Also, two Chrysler Corp Emissions Recalls have been completed (see my photos) No. 332T & No. 343T ~ neither recall describes removing the distributor vacuum advance line (it was missing when the truck arrived from California...) The recalls involved the carb choke, O2 sensor, CAT, ignition timing...

Well, it's A good thing I don't need to use the truck often or go very far... I miss having (MY) garage & hate having to pay $4.00 hour to use the military auto skills centers... But, they have lifts, tools, mechanics on duty, etc...

It's all good, the truck is more toy than work horse and it will help keep my brain active trying to figure out all it's mysteries... New cars are so easy to diagnose compared to this rascal... I feel as though I am in High School Auto Shop all over again except now I am REALLY old n' lazy...

The Forum's Fun,
George

[geezer101]

No vac advance or it being incorrectly hooked up will wreak havoc with how the engine runs. LOL neanderthal tech is waaaay easier to work with - older the better. It was when the powers that be started demanding vehicles emit daisy farts that they became a disaster to work on. Take note of what the Cali recall affected - mainly the O2 sensor and the ignition timing. They nerfed the engine in the process. Once you can get it to run smoothly, you will be able to tune the engine by ear and make some extra torque/HP. There are instances where 'the book' doesn't always yield optimal results (like setting mechanical valve lash adjusters - you can go over them 10 times with feeler gauges and it will still sound like a machine gun...) Lucky it has an ECM distributor in it. You ever tried dialling in dwell angle in a points distributor? Took me a long time to get the feel for it (another situation where 'the book' is not super helpful and turned it into an act of frustration...but getting it 'perfect' was rewarding)
If you have a timing light (just to check base timing before dialling in optimal tune), a dwell/tach meter (diagnostic tool to check for misfire and for setting up the appropriate rpm range for tuning), feeler gauges (you're only gonna use them for setting your plugs but you'll need them) and a hydrometer (the best way to test the condition of your battery) you will soon be getting to know exactly how to get your truck running sweet
A pocket multimeter is something you should have on hand. Lets you know if your alternator is actually charging and good for hunting gremlins in the electrical system.

[xboxrox]

STOCK CALIFORNIA EMMISSONS TRUCK

HELP from around the world, including Australia, WOW; the net is powerful...

geezer, you sound like the mechanics at the MCBH Five-O-Motors (marine base Kaneohe, auto hobby shop/skills center) When the wife n' me work on the truck over there; they rescue me & my mistakes... I get a little embarrassed and just tell the wife: "Honey, that's the difference between me and them, they are mechanics and I am not, LOL, sad... Alternator check, (?) I feel lazy thinking about trying to do a new trick for this old dog; but...

Giovanni's comment on a "Power Valve & it's diaphragm" mirrors almost exactly what one of the Five-O-Motors mechanics said: "check your fuel enrichment system..." If, I can learn & perform the tests on the "Power Valve" where do I get replacement parts if needed..? Oh boy, I really miss mainland wrecking yards; I called them "Going to the beach" now in Hawaii, I have real beaches & no DIY wrecking yards... ain't Life Grand..!

Well, I think the photos I referenced above, are uploaded now...

Maybe the wife will let me buy a DMM for auto mechanics..?


TYVM, progress reports & more questions coming soon,
Make it a Great Day guys
George

[geezer101]

An alternator check with a multimeter is super simple. Start the engine and run the meter over the battery on 20V DC - it it's showing move than 13v, it's working. If you've had to jump start or trickle charge it overnight and you're not 100% sure if the battery is toast or it's the alt, this is a good way to know where to start. This is the time you break out the hydrometer and check the battery cells if the battery is showing good voltage but the engine is struggling to turn over.

[xboxrox]

Progress Report 6/15/2018

Truck is running better with new spark plugs & new ignition coil AND steps taken as follows:

After learning where the distributor vacuum advance line should be connected per the emission label; I saw today that it was connected to the vacuum source correctly... Then it took less than a minute to find the distributor end dangling down over the alternator..! The truck runs a little better now that the distributor is properly connected to vacuum... Ditto for also removing the extra vacuum line I had incorrectly connected to the "Vacuum Switch"

-----------------------------------------------------------------------------

REF: Fuel System Chap 14 (Factory Service Manual..?)

[xboxrox]

Just a thought..? The Mikuni carburetor has a power valve to inject gas through an extra jet (power jet) when the engine is under heavy load... It operates with a vacuum diaphragm & spring... Just maybe, the gas mileage might be improved now that the distributor vacuum line is connected..? Will check the mileage after next gas fill...

REF: http://www.mightyram50.net/vbulletin...ory-manual-PDF

Thank You camoit

[geezer101]

If you're not getting enough advance you will compensate for power being down by planting your foot, so yes, now it's hooked up you'll gain economy. All mech Mikuni carbs don't have a 'power valve' - they have an accelerator enrichment jet (mechanically operated pump off the throttle - single shot of fuel from closed throttle), the secondary vacuum actuator (big vacuum servo that only functions on-throttle once the primary has opened), altitude compensator (*another vacuum operated servo - not on all Mikuni carbs) and an often overlooked auto choke release assist (small vacuum diaphragm on the auto choke assembly) The electronically controlled Mikuni has up to 3 electric solenoids that open and close air metering galleries internally. I learned how to fudge them by changing which metering circuits to open and close and how to get them into an 'economy' or 'sport mode' - a really awful carb to meddle with...

[Giovanni89]

Do emissions laws in Hawaii let you put a weber on? I'm would think you could pick up a used setup for not too much money, or just go with a new one. I'm glad I've never had to deal with the mikuni. I have the one original to the truck in a box. Previous owner had it removed for a no start condition that kept coming back. No Idea what is wrong with it, but You could have it for nothing if you pay the postage. Spare parts or one to rebuild while the other sits on the truck.

[geezer101]

...I have the one original to the truck in a box. Previous owner had it removed for a no start condition that kept coming back. No Idea what is wrong with it, but You could have it for nothing if you pay the postage. Spare parts or one to rebuild while the other sits on the truck.

This is not a bad idea if you can get a complete kit for it and have all the ancillary components for it on hand (auto choke release, a working secondary vac servo - hopefully the wax pellet choke is good as they are hard to come by and even though I have tried to pull one apart, I've never been successful in taking it out of it's housing without wrecking it) Simple rules - break it down into it's 3 base components (expect a stubborn fuel bowl cover screw or 2), don't lose the brass float and ball bearing inside of the carb body in the process (this will really piss you off if you send them flying or can't remember what gallery they came out of), get it thoroughly clean and trim any overhang from the paper gaskets - including the metering galleries in it (these carbs are sensitive to their own internal vacuum and even a partial blockage can nerf them) and do all of the adjustments while it's apart like resetting the auto choke butterfly shaft tension and throttle shaft stops. It may take a few strip down and reassemblies to get it right but if you take your time and be patient with it (and there's no actual defect with it like a worn shaft or a warped throttle plate), you'll have a solid spare carb waiting to go.

[xboxrox]

Well..? Hope I don't never have to rebuild anything (x'd fingers) especially if I have to learn even 1/4th of the carburetor things in your post Mr. geezer [dropping the R in your name geeze..!] In High School, I rebuilt a four barrel Carter WCFB, times were so simple back then... Truth is I hope to never buy another automobile if this little truck can survive... So, the reality is that I'll learn or lose using this little gem (Mitsubishi built most of the enemy planes in WWII) and they lost, mmm!

I did browse the O'reilly Walker kit # 15793E rebuild kits online but they don't seem very complete; Giovanni, your offer is a swell deal "IF" I can locate a good parts source, BTW THANKS, for now wait... I did not bookmark the web page but I will try to upload a Walker parts info PDF that I saved as a reference... My truck's carb # is 32-35 DID (no TA or TF) I think two screws hold a flanged ring on the very top of the carb which hides one of the 1st numbers..? other numbers include 2207 & 7Z08...

The realty is IMHO, just buy a complete rebuilt carburetor if this one gives up & then hope what they send is even close..?

Hawaii reality is IMHO, laid back, no rules for engine emissions... But, I want to keep the original windup spring for my toy truck...

Hope the REF doc is attached & viewable,
You gents make this forum Great,
George

[geezer101]

*Japan might have lost the war back in the day but they ran out of resources. Look at what they achieved with access to R&D and materials, they are a clued in bunch. We shot down their planes - and now we're driving their trucks (both made by the same company...ironic and poetic ain't it)

[xboxrox]

You are Sooo right geezer; gimme just $1.00 for every Toyota Tacoma truck & $1.00 for every Honda CRV suv on the road here in Oahu, and I would be a rich man... Windward Ford here in Kailua tries to sell premium model Ford F-150 & F-250 trucks for anywhere between $45,000 to $130,000... My little Dodge Ram50 was more than worth it to spend $1,100.00 to ship it over here; it is paid in full as well...

NHK TV News was showing Japanese food being prepared by robots for sale in Saudi Arabia; robots doing so much in Japan...

Thank you Japan & US Navy for letting me have a pretty rare & pretty cool little truck...

CHECK OUT my photo albums, new photos uploaded today...

[xboxrox]

UPDATE new gas mileage numbers ~ truck got 20 MPG this time around @ 128 miles / 6.4 gallons to fill..!

Connecting the distributor vacuum line & STP fuel system cleaner helped lot...

Thanks for the help guys...

[Giovanni89]

I think you'll get a few thousand more miles out of your plugs this time around!

[xboxrox]

Maybe so...

[Ingham]

Just checked out your photo album, Xboxrox. I'm jelly! What an amazing truck you have, bro. I love it!

[xboxrox]

Thank you Ingham,

KYB shocks have arrived, will take photos of install & post the difference in ride... soon